High-frequency-link (HFL) power conversion systems (PCSs) are attracting more and more attentions in academia and industry for high power density, reduced weight, and low noise without compromising efficiency, cost, and reliability. In HFL PCSs, dual-active-bridge (DAB) isolated bidirectional dc-dc converter (IBDC) serves as the core circuit. This paper gives an overview of DAB-IBDC for HFL PCSs. First, the research necessity and development history are introduced. Second, the research subjects about basic characterization, control strategy, soft-switching solution and variant, as well as hardware design and optimization are reviewed and analyzed. On this basis, several typical application schemes of DAB-IBDC for HPL PCSs are presented in a worldwide scope. Finally, design recommendations and future trends are presented. As the core circuit of HFL PCSs, DAB-IBDC has wide prospects. The large-scale practical application of DAB-IBDC for HFL PCSs is expected with the recent advances in solid-state semiconductors, magnetic and capacitive materials, and microelectronic technologies.

Overview of Dual-Active-Bridge Isolated Bidirectional DC–DC Converter for High-Frequency-Link Power-Conversion System

The main objective of this two-part state-of-the-art paper called “Recent Advances in the Design, Modeling, and Control of Multiphase Machines” is to present latest contributions in the multiphase machines' field. The first part of this paper focuses on the recent progress in the design, modeling, and control, whereas the drive is in healthy operation. This second part presents relevant contributions in two not analyzed fields. The first is in relation with the use of the additional degrees of freedom of multiphase machines and the exploitation of their fault-tolerant capabilities without adding extra hardware. The second one analyzes multiphase generation, particularly in grid-connected wind energy conversion systems and stand-alone applications. Recent progresses are shown and open challenges and future research directions are discussed.

Recent Advances in the Design, Modeling, and Control of Multiphase Machines—Part II

The state of the art of wind energy conversion systems and technologies: A review

This paper proposes a new high step-up dc-dc converter designed especially for regulating the dc interface between various microsources and a dc-ac inverter to electricity grid. The figuration of the proposed converter is a quadratic boost converter with the coupled inductor in the second boost converter. The converter achieves high step-up voltage gain with appropriate duty ratio and low voltage stress on the power switch. Additionally, the energy stored in the leakage inductor of the coupled inductor can be recycled to the output capacitor. The operating principles and steady-state analyses of continuous-conduction mode and boundary-conduction mode are discussed in detail. To verify the performance of the proposed converter, a 280-W prototype sample is implemented with an input voltage range of 20-40 V and an output voltage of up to 400 V. The upmost efficiency of 93.3% is reached with high-line input; on the other hand, the full-load efficiency remains at 89.3% during low-line input.

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A Cascaded High Step-Up DC–DC Converter With Single Switch for Microsource Applications

A novel bidirectional dc-dc converter is presented in this paper The circuit configuration of the proposed converter is very simple The proposed converter employs a coupled inductor with same winding turns in the primary and secondary sides In step-up mode, the primary and secondary windings of the coupled inductor are operated in parallel charge and series discharge to achieve high step-up voltage gain In step-down mode, the primary and secondary windings of the coupled inductor are operated in series charge and parallel discharge to achieve high step-down voltage gain Thus, the proposed converter has higher step-up and step-down voltage gains than the conventional bidirectional dc-dc boost/buck converter Under same electric specifications for the proposed converter and the conventional bidirectional boost/buck converter, the average value of the switch current in the proposed converter is less than the conventional bidirectional boost/buck converter The operating principle and steady-state analysis are discussed in detail Finally, a 14/42-V prototype circuit is implemented to verify the performance for the automobile dual-battery system

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Analysis and Implementation of a Novel Bidirectional DC–DC Converter

This paper presents a novel topology named forward-flyback bidirectional DC-DC converter (BDC), which is a hybrid of forward and flyback converters The windings of forward and flyback transformers are connected in series on the primary side and in parallel on the secondary side The proposed converter has no startup problem and no high voltage spikes on the switches, which otherwise are inherent for current- and voltage-fed-type bidirectional converters It is easy to achieve soft switching by proper control and design The built-in flyback transformer acts as a filter inductor, so the current ripple is smaller than flyback BDCs In this paper, the operation principles and characteristics of the proposed topology are analyzed in detail The advantages aforementioned are verified with experimental results of a 300-W prototype

Novel Forward–Flyback Hybrid Bidirectional DC–DC Converter

This paper proposes a novel phase-shifted zero-voltage and zero-current-switching (ZVZCS) pulsewidth modulation full-bridge converter, which realizes ZVS for the leading leg and ZCS for the lagging leg. A blocking capacitor is added in series with the primary winding of the transformer to make the primary current decay to zero during zero state to ensure ZCS for the lagging leg. In order to prevent the primary current from reversing during zero state, two diodes in series with the lagging leg are added. The principle of operation, steady-state analysis, and design procedures are presented. The experimental results are also included to verify the theoretical analysis.

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A novel zero-voltage and zero-current-switching PWM full-bridge converter using two diodes in series with the lagging leg

We present a new topology of hybrid excitation synchronous machine (HESM) and describe operational principles and features of the new configuration. Using the radial/axial distribution of the magnetic field, we develop an equivalent magnetic circuit model. We obtain magnetic flux, flux density, and induced voltage with various electrical magnetomotive forces by calculating the nonlinear magnetic circuit equation. We studied the Influence on the radial magnetic field of the axial magnetic field by 3-D finite-element method. The results are in good agreement with calculation by our magnetic circuit model. Our findings indicate that the air-gap flux density of a flux-concentrating HESM is high and the magnetic field in the air gap can be successfully regulated. Experimental results of 3 kVA prototype machine verify the feasibility of the structure and the correctness of our analysis.

Principle of Operation and Feature Investigation of a New Topology of Hybrid Excitation Synchronous Machine

The doubly salient brushless dc generator (DS-BLDCG) is constituted by a doubly salient electromagnetic generator (DSEG) and the associated rectifier circuit. The DS-BLDCG is suitable for the automobile auxiliary power unit (APU) application due to its merits of simplicity, high robustness, low cost, and flexible control. Since no constraint is imposed to the number of phases of the onboard brushless dc generator, the polyphase DSEG can be employed. In this paper, a 3-phase 12/8-pole DSEG and a 4-phase 16/12-pole DSEG with a rectifier circuit for the APU application are proposed. The taper stator pole and broadened rotor pole structure utilized to increase maximum output power is introduced in the four-phase DSEG design. Based on the two-dimensional (2-D) finite-element method (FEM) and field-circuit coupling analysis, a comprehensive comparison is presented. The 16/12-pole DS-BLDCG with broadened rotor pole exhibits lower peak value of the phase inductance yet larger negative phase current commutation overlapping angle. The rectifier circuit of the 16/12-pole DS-BLDCG is more complex and the copper consumption of the 12/8-pole DS-BLDCG is slightly less. A prototype 12/8-pole DS-BLDCG for the APU application is designed and developed. Both the simulation and experimental results indicate that the developed DS-BLDCG is a promising option for automobile APU application.

Analysis and Verification of the Doubly Salient Brushless DC Generator for Automobile Auxiliary Power Unit Application

This paper proposes and implements a new topology of hybrid excitation doubly salient brushless dc generator (HEDS-BLDCG). Configuration and flux control principle of the generator are presented. Two-dimensional finite-element methods are used to investigate the static field distribution characteristics of this new type of generator. Field-circuit coupled analysis is successfully performed, and the output characteristics of different windings are obtained. A prototype HEDS-BLDCG is designed and developed, and the experimentation is also given to verify the validity of the proposed brushless dc generator with one and dual terminal outputs. The results confirm the excellent field-regulation capability of HEDS-BLDCG, and the rectified output of the permanent-magnet part can serve as the independent power of the excitation winding when the HEDS-BLDCG has two sets of output windings.

Yangguang Yan

Papers

Novel Forward–Flyback Hybrid Bidirectional DC–DC Converter

A novel zero-voltage and zero-current-switching PWM full-bridge converter using two diodes in series with the lagging leg

Principle of Operation and Feature Investigation of a New Topology of Hybrid Excitation Synchronous Machine

Analysis and Verification of the Doubly Salient Brushless DC Generator for Automobile Auxiliary Power Unit Application

Investigation of a New Topology of Hybrid Excitation Doubly Salient Brushless DC Generator